Photographic-printing process and solution and material therefor



V Improvements in Photographic-jPrinting] To all whom it may concernYORK ALEXANDER FERDINAND sorrwliit'rz, O F LONDOM-ENGLAND.

rnoroenArrrro-rmnrrne PROCESS AND sensation ANDQI viATE rA L rHEEEEoni=1 Specification of Letters Batent;

Patented A p r 25,

NoDravvingf f/ f npplicationfiled seamtefij14,"1 21. saa1*seesaw-j I 'Beit knownthat 1,,Y0RK V FERDINAND SornvAn'rz, a citizen of the GermanBepubliqresiding in London'din the county of Middlesex and KingdomofQEngland, have invented. certain new andf 'useful Processes andSolutions i and Materials Therefor, (for which havefiled an application'in England, No. 24,208, dated August, 20, 1920,) of the followingisfla'spe c ifij-l This invention relates t'o improved photo graphicprinting papers and the like sensitized inaterials and and treatin thesame. i I y In nitedstates Patent.'No. 710,019 dated Septfi30, 1902,reissued No. 13,144

. dated Aug. 16, 1910 andagain reissued No. 13,162;dated Oct.25, 1910'and No; 962,78

dated June 28,"1'1910,.I described photographic 7 emulsion containingsilver phosphate in the insoluble form; According to my present,invention einploypsilverl "phos phate in dissolved form, andsuchfasolution is preferably"prepared by treating silver phosphate with,ferric oxalate though other compounds l'can L be used jas hereafter;dcscribed. Photographic vmaterial sucli i 'as' paper may be sensitizedby thefuse of such'a solution which may be developed by theal;

kali salt of anorganic acid.

' Such solutions of silver phosphate be prepared by treating either theortho-phosphate, meta-phosphate vor pyro-phosphate of silver, especiallywhen'freshly prepared with a Isufli'cient quantity of ferric salts oforganic acids, 'more particularly ferric oxalate orcitrate Which must befree from the corresponding ferroussalts' The ortho-phojsphateread} Iily dissolves in .a solution of such saltat ordinai'y temperature, but.the'pyro-phosphate and meta-phosphate require :to be heated to about 50to 609C. Possibly the pyro or meta-salts are converted into theortho-phosphate prior to or during. solution. Iii any case the solutionsso obtained appear to rep? resent either true or colloidal 'solutions ofsilver phosphate and will, be hereafter de scribed as Solutions.

It maybe added that ,itfis" not: ecessar to isolatethe'silveri-pho'sphate, but that prod- AL X nER processes of roauem netsof reaction between silver' nitrate and" an alkali phosphate may: be"used as here-j after described, preferably tvith the 2'LClc1it- '1 onof a certain quantity of an organic acid, and in practlceit is notnecessary 'to removeithe soluble sodi'mn or other,iii't m te produceddouble decomposition. a M 1 -The silver i phosphate in; the freshlyprepared forni ,"e.'gi' the product of double decomposition" abovedescribed, fi s then treated with agisolution of the ferric salt; of jan organicfiacid, preferably" ferric; oxalate which appears to {be themost satis-T factory, when a solutionis obtained which isfound to ecapable er resiervation inthe dark] fur prolonged periods "while sunre;- Inainingphotographically perfect. Such solutions under Whateverconditions they may havebeen'prepared appear always to possess thesaniespeed a'nd gradation and.

to produce the same tone pib fidfidithe lnatul jfe unchanged, y

jThe sensitizing 'solutio nfso obtained may be treated {to increase itsviscosity, e; g] by and the proportions ofthecomponents are miXing'thefinished solution Withjsuitable' colloids such as solutions of gelatine,gum L be employed, e. g. paper, fabric, or glass, the

latter after having been coated with some insoluble, material, ve. g.hardened gelatine,

WhichvvilL absorb th'e'solution vvhichisgthen v dr ed when it isready tobe exposed behind. a negative drawing, stencilled design, orally; I

other device producing a developable -image' by actinic radiation. Thematerials could be used in'afcamerawif desired but theex pos u-re wouldhave tobe extremely "long, 5

a Af r exp s e h -Pr n is? d el bi treatment with'an alkali salt of anorganic actiQnof the reagents, but I may state that as far as I am awarethe following reaction takes place, though it will be understood that ein enti is not. limi ed. o the pa ticular h ory e pounde alth ugh thi ibelie ed.

o he c u a e It eppea-rst a When se si= t d mat ria Prepa ed om the aboe solun is e po ed t actinic gh tw d fferent photochemical actions areproduced, viz, the ferric salt is reduced to ferrous se'lt in propor ionto the monntof gh re ei e and the s lver p o phate, ich p ss sses all thpr pe req i d or he productio of pe f ct image, is at th same imaffected also in proportionto the amount of g ece ved. 'Now' when he eacion has e 'p ace, he ferrou compoun p o ced will act as a .developerforthe silver compou d in p e ce of the. alkalis l of the organic acid,and, it will be seen that the amount of the developer is automaticallyproportionate to the ttmount of exposure which has taken place, so thataccording to h pr en invention, th d el pment is x mely successful- IWllhIlOW illustrate the invention more clearly by the followingexamples; the operation should be carried out in yellow light or takingother precautions to exclude actinic light.

. Example A.

7 ware dish (mortar) place.-

A8 gr. silver nitrate.

2 .8 gr. sodium phosphate '(Na H'PQ .l2H O).

70.0 cc. distilled water of ordinary temperature, rub up with pestleuntil the salts have dissolved, and the yello'w silver phoscrystals,free from lead) rub up till the citric acid has dissolved, filterthrough pure paper. Preserve in glass-stoppered. bottles of'deep yellowglass in the dark.

E sample B.

Sensitizer with a colloid I (gelatine). If an addition efg. of gelatinebe-required, proceed as follows:

Make *upthe filtered sensitizerex'aotly as described above, but insteadof theZO cc..of

without gelatine described above.

temperatures above 10 C.v It is evidentthot e exac ly th sa e, as t eofhe s siti en This gelatine sensitizer remains liquidat V sensitizerswith any other suitable colloid may be prepared by simply substitutingsuch colloid forthe gelatine of the above example. I declare that what Iclaim is a? p 1. A photographic solution containing silver phosphate anda compoundfadapted to yield a developer under the action. of light. 2.,A photographic solution [containing silver phosphate. and the. ferri slt an rganic ac d. I 3. Photographic sheet material sensitized by silverphosphate and the ferri Saltof an organic acid. 7 4. The process of vpreparing a photos graphic solutionwhich consists in dissolving freshlyprecipitated silver phosphate in a solution'of the ferric salt of an.organic acid. 4

'5. The process of preparing a photographic solution which consists indissolv:

ing silve phospha by he aid of the erri altf f an organic a id.

6. The process of sensitizing a photd.

graphic material which consists in precipitilting silver phosphatedissolving the the solution to the material.

7. The process of sensitizing photographic material which comprisespreparing a solution containing silver phosphate and a body adapted toyield a de lope on ex.

osure.

8. A photographic; solution containing silver h sphate and ferricoxalate. 9., photographic sol tion: co t n g silver phosphate, theferric salt of anorganic acid. and n excess o ganic aci freshlyprecipitated phosphate and apply '10-. The proc ss. ofobtaining-photographic images which comprises senitizing a sursigned myname this 25th clay of August,

face with a solution containing silver phos- 1921, in the presence oftwo subscribing phate and the ferric salt of an organic, acid, itnesses.

exposing the same to 'actinic light and Y K'A X N R RD A S HWARTZ- 5cleveloplng with a solution of an alkali salt \Vitnesses: 1

of an organic acid. ERNEST HENRY ROBERTS,

In wltness whereof, I have hereunto GEORGE PERCY SKELDEY.

